Include project's v1 ID in export requests

If a project was imported from v1, include its v1 ID when making an export request back to v1.

Use case: v1 project exported via ScholarOne and then migrated to v2 needs to be linked up to its earlier v1 export records.

services/web/app/coffee/Features/Exports/ExportsHandler.coffee

@@ -56,6 +56,7 @@ module.exports = ExportsHandler = self =
 					rootDocPath: rootDoc[1]?.fileSystem
 					historyId: project.overleaf?.history?.id
 					historyVersion: historyVersion
+					v1ProjectId: project.overleaf?.id
 				user:
 					id: user_id
 					firstName: user.first_name

services/web/test/unit/coffee/Exports/ExportsHandlerTests.coffee

@@ -64,6 +64,7 @@ describe 'ExportsHandler', ->
 			@project =
 				id: @project_id
 				overleaf:
+					id: @project_history_id # for projects imported from v1
 					history:
 						id: @project_history_id
 			@user =
@@ -90,12 +91,13 @@ describe 'ExportsHandler', ->
 				.should.equal true
 
 			it "should return export data", ->
-				expected_export_data = 
+				expected_export_data =
 					project:
 						id: @project_id
 						rootDocPath: @rootDocPath
 						historyId: @project_history_id
 						historyVersion: @historyVersion
+						v1ProjectId: @project_history_id
 					user:
 						id: @user_id
 						firstName: @user.first_name
@@ -126,6 +128,7 @@ describe 'ExportsHandler', ->
 						rootDocPath: @rootDocPath
 						historyId: @project_history_id
 						historyVersion: @historyVersion
+						v1ProjectId: @project_history_id
 					user:
 						id: @user_id
 						firstName: @custom_first_name